The field of the invention relates generally to explosion proof motors and, more specifically, to systems and methods for isolating a conduit enclosure attached to an explosion proof motor.
The National Fire Protection Association (NFPA) defines an explosion proof apparatus as, an “[a]pparatus enclosed in a case that is capable of withstanding an explosion of a specific gas or vapor that may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and that operates at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby.” The explosion proof designation does not ensure that an apparatus is incapable of exploding, but rather that the apparatus is capable of withstanding an explosion without causing damage to the immediate surroundings of the apparatus beyond a certain level.
Explosion proof motors are a class of motors that are constructed to contain an explosion, as well as to prevent the release of gases. Motors regularly include a conduit enclosure, through which electrical leads pass from the motor. For explosion proof motors, the pathways for the electrical leads represent potential paths for explosive flames, forces, and gases. At least some known motors seal the electrical lead pathways from motor to conduit enclosure to contain an explosion within the motor body.
At least some known methods of isolating a conduit enclosure for an explosion proof motor use slow-curing sealing compounds that are poured into molds within the motor's stator assembly. The motor's electrical leads extend through an opening, and packing material insulation sheets are used to isolate an area within the motor stator in which the sealing compound is poured. However, in such motors, the sealing compound must be applied to a large area, which increases the costs and time to manufacture such motors. Moreover, errors during the sealing process may cause the entire motor's stator to be rendered unusable, thus leading to additional manufacturing expenses.